package javacore.stream.javacore;

/** 
 @version 1.01 2004-05-11 
 @author Cay Horstmann 
 */

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

/**
 * This program tests regular expression matching.
 * Enter a pattern and strings to match, or hit Cancel
 * to exit. If the pattern contains groups, the group
 * boundaries are displayed in the match.
 */
public class RegExTest
{
    public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter pattern: ");
        String patternString = in.nextLine();

        Pattern pattern = null;
        try
        {
            pattern = Pattern.compile(patternString);
        }
        catch (PatternSyntaxException e)
        {
            System.out.println("Pattern syntax error");
            System.exit(1);
        }

        while (true)
        {
            System.out.println("Enter string to match: ");
            String input = in.nextLine();
            if (input == null || input.equals(""))
            {
                return;
            }
            Matcher matcher = pattern.matcher(input);
            if (matcher.matches())
            {
                System.out.println("Match");
                int g = matcher.groupCount();
                if (g > 0)
                {
                    for (int i = 0; i < input.length(); i++)
                    {
                        for (int j = 1; j <= g; j++)
                        {
                            if (i == matcher.start(j))
                            {
                                System.out.print('(');
                            }
                        }
                        System.out.print(input.charAt(i));
                        for (int j = 1; j <= g; j++)
                        {
                            if (i + 1 == matcher.end(j))
                            {
                                System.out.print(')');
                            }
                        }
                    }
                    System.out.println();
                }
            }
            else
            {
                System.out.println("No match");
            }
        }
    }
}